<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: pink;
        }
        #d1{
            margin-left: 50px;/*向左*/
            margin-top: 50px;/*向上*/
            margin-bottom: 30px;/*向下*/
            margin-right: 50px;/*向右*/
            margin: 100px;/*向四个方向赋值都是100px*/
            margin: 50px 100px;/*上下50px 左右100px*/
            margin: 10px 20px 30px 40px;/*上右下左分别为10 20 30 40顺时针赋值*/
            /*margin: auto;!*自动居中*!*/
        }
        #d2{
            /*外边距上下塌陷问题：上下相邻的兄弟元素彼此添加外边距取最大值*/
            margin-top: 50px;
        }
        /*行内元素上下边距无效*/
        #s1{margin-right: 50px}
        #s2{margin-left: 50px}/*左右相邻彼此添加外边距两者两者相加*/
        #big{
            width: 200px;
            height: 200px;
            background-color: red;
            overflow: hidden;/*解决粘粘问题*/
        }
        #big>div{
            width: 50px;
            height: 50px;
            background-color: blue;
            margin-left: 50px;
            /*外边距塌陷问题导致父子元素的上下边距取最大值出现粘粘的问题*/
            margin-top: 50px;
        }
    </style>
</head>
<body>
<div id="big">
    <div></div>
</div>
<span id="s1">span1</span>
<span id="s2">span2</span>
<div id="d1">div1</div>
<div id="d2">div2</div>
</body>
</html>